Agricultural vehicles, such as tractors and combines, are ubiquitous in the agricultural industry. As an agricultural vehicle travels across a field, agricultural processes such as plating and/or fertilizing are performed by an implement associated with the vehicle. One particular class of implements, such as planters and air carts, incorporate a low pressure tank housing a substance (e.g., seed, fertilizer, and the like) prior to its application. The tank is typically connected to a pressurized delivery system to meter and deliver the contents of the tank to the field.
The tanks used are relatively large and bulky having a typical volume between 30 bushels [960 quarts] and 60 bushels [1920 quarts] for a typical planter to over 100 bushels [3200 quarts] for air carts. Depending upon the application, the tanks may be pneumatically pressurized to between 10 ounces per square inch [4.3 kilopascals] and 16 ounces per square inch [6.9 kilopascals] to facilitate delivery of the contents. Tanks are typically made from plastic, such as polyethylene, to enhance durability, ensure chemical compatibility with the tank contents, and accommodate the delivery pressure; however, tanks may be made from any other suitable material, such as steel.
Several issues arise in relation with the typical pressurized tank, and specifically, in connection with the sealing interface between the cover and the opening formed in the tank. First, due to the relatively large size of the tanks and the desire to maintain economical production, manufacturing tolerances of typical molded tanks introduces variation in the dimensions of the opening formed in the tank. Second, the tanks are susceptible to deformation caused by the pressure differential between the internal pressure required for delivery of the substance and the external atmospheric pressure. Over time, these two problems can combine to deteriorate the quality of the seal formed between the tank and the related cover.
In connection with the operation of the tank latch assembly, the large size of the tanks and associated covers present additional impediments to efficient operation of the tank cover and latching assembly. First, the placement of the tanks typically requires some type of latter or platform to reach the cover and move it between an open and closed position. Second, the desire to create a seal about the entire perimeter of the tank opening often leads to latch assemblies that are difficult to operate due to awkward placement of the latches and locking mechanisms used to secure the cover to the tank. For example, the mechanisms may require one to reach multiple areas around the cover to both engage and disengage the cover. These problems combine to impede the ease of operation of traditional low pressure tank latch assemblies.
As a result, a need exists for a pressurized tank cover latching assembly that effectively seals the tank opening and is convenient to operate.